That is certainly one interpretation of the OPs question. And you are right: there is no silver bullet/magic formula/secret recipe. There are some nuances in the way the original question is framed. So the framing that 'a way to quickly and accurately determine if your idea is on the right track' is not good - ideas aren't good or bad, they are never on the right or wrong track - they are what they are, just ideas. Its the execution of an idea that paves the way and propels the idea in a specific direction. So, while there isn't (and may never be) a great tool/process/discipline to evaluate ideas - there are tools/processes/disciplines available to evaluate execution.
So, I read the question slightly differently - and I would say there is definitely something here. I can imagine a consulting service (problem-solving and execution discipline for startups - kinda like what mckinsey does for the fortune 500 :)) that could bring structured problem solving, fact-based de-biasing (countering delusions of optimism), focussed execution, research, 'talking to users' (the famous YC mantra) and (I don't have good name for it) lets call it "learning from experience and experiments of others" etc may be possible as a service.
Its the help a startup needs between "office hours" and execution. I do think that there is a piece missing here, that can be developed.
> "Its the help a startup needs between "office hours" and execution. I do think that there is a piece missing here, that can be developed."
Pretty much agree with everything you said, this is a good unpacking of what I was trying to briefly convey in the OP.
For example, if one of the founders is strong in Biz Dev, then they probably don't need this (though some level of assistance would still be helpful), but if this is not the case, then getting guidance and potentially full-service assistance with an all-in effort in gaining customer feedback in a valid way that could be just the frequency shift that determined success or failure in an otherwise solid product/idea.
Basically you would be taking the product from something potential customers respond with "maybe" into something they say "Heck yes, take my money!"
So, I read the question slightly differently - and I would say there is definitely something here. I can imagine a consulting service (problem-solving and execution discipline for startups - kinda like what mckinsey does for the fortune 500 :)) that could bring structured problem solving, fact-based de-biasing (countering delusions of optimism), focussed execution, research, 'talking to users' (the famous YC mantra) and (I don't have good name for it) lets call it "learning from experience and experiments of others" etc may be possible as a service.
Its the help a startup needs between "office hours" and execution. I do think that there is a piece missing here, that can be developed.